acoustic levitation

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Acoustic levitation

The use of intense acoustic waves to hold a body that is immersed in a fluid medium against the force of gravity without obvious mechanical support.

Levitation can occur in the presence of fluid flow, including the back-and-forth fluid flow produced by the passage of an acoustic wave. Such acoustically generated forces are extremely small in common experience. But intense acoustic waves are nonlinear in their basic character and, therefore, may exert a net acoustic radiation pressure on an object sufficient to balance the gravitational force and thus levitate it. See Acoustic radiation pressure

The applications of acoustic levitation in air or other gas include an acoustic positioning module that has been carried in the space shuttle and used in fundamental studies of the oscillation and fission of spinning drops. An acoustic levitation furnace has been designed to study the possibility of containerless solidification of molten materials.

Applications of the levitation of objects in liquids have included measurements of the ultimate tensile strengths of liquids, mechanical characterization of superheated and supercooled liquids, the measurement of properties of biological materials (including human red blood cells and lipids from the porpoise dome), the study of shape oscillations and interfacial tension of levitated drops, and the evaporation of charged drop arrays levitated electroacoustically. See Sound

acoustic levitation

[ə′küs·tik lev·ə′tā·shən]
The use of a very intense sound wave to keep a body suspended above the device producing the sound wave.
References in periodicals archive ?
Caption: How acoustic levitation works: Speakers create pockets of low pressure between sound waves (red and gold) that can levitate small objects.
The topics include cutting forces in helical milling processes, methods for evaluating uniformity in the lapping process, applying visualization in scientific computing technology, the numerical and flow-field simulation of acoustic levitation polishing, designing cold extrusion dies for precision gears, applying ultrasonic radiation forces, the impact of plate cylinder deformation on graphic quality, and the autonomous control of abrasive flow precision machining.
Scientists have known for years how to use sound waves to hoist particles in the air, a process known as acoustic levitation.
A partnership between SPACEHAB and Guigne Technologies Limited of Newfoundland, Canada, Space-DRUMS(tm) (Dynamically Responding Ultrasonic Matrix System) uses acoustic levitation, or sound waves, to hold fluid or solid material samples in place in microgravity while they are being processed aboard the Shuttle or ISS.
is among the first to demonstrate that acoustic levitation at high temperatures is possible in a nearly weightless environment.

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